Subject:XSLT Quick Reference Author:Minollo I. Date:30 Aug 2001 11:15 PM
sorry for the delay in answering this.
I find the "Working with XSLT" section in the Stylus Studio documentation very useful and well written (and I'm not the author! ;).
Apart from that, and apart, of course, from using the official specs as a reference document (http://www.w3.org/TR/xslt), there are several good books available on XSLT; but I wouldn't feel comfortable in suggesting one over the other.